The ERK mitogen-activated protein kinase pathway contributes to Ebola virus glycoprotein-induced cytotoxicity
The ERK mitogen-activated protein kinase pathway contributes to Ebola virus glycoprotein-induced cytotoxicity
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DOI：
10.1128/jvi.01586-06
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发表时间：
2007-02-01
影响因子：
5.4
通讯作者：
Nabel, Gary J.
中科院分区：
文献类型：
--
作者：
Zampieri, Carisa A.;Fortin, Jean-Francois;Nabel, Gary J.
埃博拉病毒是一种高度致命的病原体，可引起人类和非人类灵长类动物的出血热。在七种已知的病毒基因产物中，包膜糖蛋白（GP）单独诱导细胞变圆和脱离，最终导致细胞死亡。在缺乏粘蛋白样结构域的GP突变体（GP Delta muc）的表达水平相当的情况下，未观察到细胞毒性。GP诱导的细胞死亡是非凋亡性的，并且在此之前下调参与信号传导途径的细胞表面分子，包括某些整合素和表皮生长因子受体。为了研究GP诱导细胞毒性的机制，我们分析了参与细胞生长和存活的几种信号转导途径的激活。细胞外信号调节激酶1型和2型（ERK 1/2）的活性形式，磷酸化ERK 1/2，在表达GP的细胞中减少相比，表达GP Δ μ c的细胞，通过流式细胞术测定，在几个其他信号蛋白的情况下相反。随后分析相关激酶的激活状态和激酶活性，发现对ERK 2激酶亚型有更明显的影响。通过显性负性ERK或通过小干扰RNA介导的ERK 2敲低破坏ERK 2活性增强了与毒性相关的α V整合素表达的降低。相反，通过表达ERK 2的组成型活性形式激活该途径可显著防止这种效应。这些结果表明ERK信号级联介导GP介导的细胞毒性，并在该基因产物诱导的致病性中发挥作用。
Ebola virus is a highly lethal pathogen that causes hemorrhagic fever in humans and nonhuman primates. Among the seven known viral gene products, the envelope glycoprotein (GP) alone induces cell rounding and detachment that ultimately leads to cell death. Cellular cytoxicity is not seen with comparable levels of expression of a mutant form of GP lacking a mucin-like domain (GP Delta muc). GP-induced cell death is nonapoptotic and is preceded by downmodulation of cell surface molecules involved in signaling pathways, including certain integrins and epidermal growth factor receptor. To investigate the mechanism of GP-induced cellular toxicity, we analyzed the activation of several signal transduction pathways involved in cell growth and survival. The active form of extracellular signal-regulated kinases types 1 and 2 (ERK1/2), phospho-ERK1/2, was reduced in cells expressing GP compared to those expressing GP Delta muc as determined by flow cytometry, in contrast to the case for several other signaling proteins. Subsequent analysis of the activation states and kinase activities of related kinases revealed a more pronounced effect on the ERK2 kinase isoform. Disruption of ERK2 activity by a dominant negative ERK or by small interfering RNA-mediated ERK2 knockdown potentiated the decrease in alpha V integrin-expression associated with toxicity. Conversely, activation of the pathway through the expression of a constitutively active form of ERK2 significantly protected against this effect. These results indicate that the ERK signaling cascade mediates GP-mediated cytotoxicity and plays a role in pathogenicity induced by this gene product.